1. Field of the Invention
The present invention relates to a liquid droplet jetting-inspection apparatus which inspects or tests a liquid droplet-jetting apparatus that jets a liquid droplet from a nozzle, such as an ink-jet head, and a liquid droplet jetting-inspection method.
2. Description of the Related Art
In recent years, an ink-jet head has put in practical use, and an inspection apparatus for the ink-jet head which detects a jetting quality of the ink-jet head has already been known. This ink-jet head cause, based on a drive signal applied from a driving circuit, a pressure fluctuation or change in a pressure chamber in which an ink is stored. Due to the pressure change, an ink droplet of the ink is jetted from a nozzle communicating with the pressure chamber. Further, the driving circuit and a drive element are grounded via a ground line. In an inspection apparatus disclosed in Japanese Patent No. 3531380, a waveform of an electric current flowing through the ground line is detected; and based on the current waveform, a current waveform or a drive voltage of the drive signal outputted to the ink-jet head from the driving circuit is presumed, thereby making it possible to judge the quality of the ink-jet head (to judge the presence or absence of any jetting defect).
In this manner, in the conventional inspection apparatus, the quality of the ink-jet head is judged by detecting the waveform of the electric current flowing through the ground line. Therefore, although it is possible to judge the quality for the driving circuit, the drive element of the ink-jet head, and a signal line connecting the driving circuit and the drive element, no consideration is made for any mis-jetting (jetting failure) of the ink droplet and any bending or deviation of the ink droplet from an intended jetting direction (bending in the jetting direction) due to any clogging in the ink channel and/or the nozzle or due to any damage of the ink channel and/or the nozzle. The bending of the ink droplets is one of the factors causing the deterioration of image quality. So far, as an inspection method of the bending of ink droplet, there are proposed inspection methods such as observing the jetting condition for each nozzle with an image pickup device apparatus having an extremely short image pickup (taking or photographing) time, detecting the bending of ink droplets by actually performing the printing, etc. However, much time and effort are required for these methods.